Method for production of alcohols from olefines



June 9,1931.

LIQUID OLEFINE S. R. MERLEY METHOD FOR PRODUCTION OF ALCOHOLS FROM OLEFINES- GASEOUS OLEFINE coummme MATERIAL CONTAINING MATERIAL 16 EENZlNE-LIKE BON ACID 4 SETTLING TANK WATER 2A 2? 52 28 40" k .QRQWN 1N5.) POLY M ER "r N e Eli-.3 6 5 COOL c s 30 ,LEAo TuBE HEAVY ALCOHOL- 39 5 CONDENSER I PLYMER.LAYER 42 LIGHT POLYMERS inane LLI\LFJJ vs cowosrvsso 64S -fjE PBE- EETIJ 6'2 54 66 STEAM Con. -2

88-|0oc' 56 LEAD LlNED STILL HIGHER 84 ALCOHOL SEPARATING TANK v, {21$ fig 1190 HIGHER v cRuoE, UP TO 80C 80'-B2C arc- 6%: 7 set-53C ALCOHOL CHIEFLY KETONES GRAVITY.8|66'.82 6RAVlTY.82-.84.8 mvwwMs-ses STORAGE- ;cnuoansomom CRUDE ISOPROPYL, ISOPROPYL BUTYL ALCOHOL 5TDRA6E BUTYL STORAGE STORAGE- v m wmtoz Patented June 9, 1931.

UNITED STATES PATENT OFFICE SYLVAN R. MERLEY, OF DOVER, NEW JERSEY, ASSIGN'OR T DOEER'IY RESEARCH COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE METHOD FOR PRODUCTION OF .AlLCOHOLS OLEFINES' Application filed March 26, 1926. Serial No. 97,600.

The present invention relates to the production of alcohols from petroleum prod.- ucts,"and more particularly to the production of secondary and tertiary alcohols from olefines contained in gases from petroleum stills or in other petroleum products.

It is a known practice to form al 1 esters, both dialkyl and acid alkyl esters, cm the olefines contained in gases, and in other prodl ucts, particularly gases and products obtained by cracking a petroleum oil. In the practice of such processes, however, difiiculties have been encountered in the way of relatively low yields from the amount of olefines absorbed in the acid and especially as to olefines having more than four carbon atoms, in

the way of producing an undesirable amount of bad smelling and difficultly disposable material commonly'known as polymers, and

' in the way of producing alcohols of bad odor.

It is the principal object of the present in vention to provide a process for producing alcohols from petroleum roducts which shall avoid or materially re uce each of the difficulties just mentioned.

Further objects of the present invention will be apparent to those skilled in the art.

from the following description, the novel features of the invention being particularly pointed out and claimed in the appended claims.

In carrying out the roduction of alcohols from petroleum pro ucts as referred to above, the olefines have been absorbed in a mineral acid, commonly sulfuric acid, with the production of a mixture of alkyl esters. When using di-hydrogen or tri-hydrogen acids, acid esters have commonly been formed although some normal esters have probably occurred in the mixture. The mixture of acid esters has then been diluted with water and distilled for the production of alcohols.

In case, however, the mixture of esters 'con-.

tains normal alkyl esters, it has been the practice to add acid to the mixture as well as water before distilling so that the distillation for alcohol production should start with a dilutemixture of acid alkyl esters.

. The present invention, however, is not limited to the production of alcohols from ture of acid esters.

It has been found in spite of care employed that a certain amount of bad smelling substantially valueless compounds, commonly 55 called polymers, has been formed at the time the olefines were absorbed in the acid. Furthermore, an additional quantity of such bad smelling compounds has been formed during the distillation for alcohols in spite of attempts to minimize their production by diluting the esters before distillation. An im portant difiiculty has been that the polymers formed during distillation have been produced from the heavy and more valuable alkyl radicals of more than four carbon atoms. The crude dilute mixture of alcohols a mixobtained from the distillation-of the dilute mixture of esters hasqalways contained therefore a considerable percentage of the socalled polymers whosepresence has depreciated the value of the alcohol, and has caused expense in their removal from the alcohols.

I have discovered that the breaking down 7 of the alkyl radicals during distillation can be prevented when distillation of. the acid ester mixture is carried on at atmospheric pressures by maintaining the acid concentration below a point equivalent to 15% of sulso furic acid (H SO For instance, if the mixture of esters is diluted with substantiallyfour volumes of water and distillation at atmospheric pressure is thereupon begun to drive off alcohols, it is necessary to add water to the mixture undergoing distillation to maintain the acid concentration below the equivalent of 15% sulfuric acid in order that none of the heavy alkyl radicals be broken down during distillation to form polymers.

If the precaution just mentioned is taken, no v polymers will be formed during distillation of the alcohols fromthe acid mixture. However, the mixture of alcohols that is driven overhead with only this change in conditions will be contaminated b the polymers in the acid mixture that were ormed during absorption of the olefines in the concentrated acid. Also the time of distilling the esters is considerably'increased. It is preferred therefore according to the present invention to conduct the process for forming alcohols from olefines in accordance with the following description, thereby obtaining the alcohols in a condition substantiall free from polymers as Well as obtaining t e advantage just described with reference to avoiding the destruction of heavy alkyl radicals. It will be understood however, that the method of conducting the distillation of the ester mixture substantially immediately after dilution with an acid concentrationbelow that equivalent to 15% sulfuric acid and maintaining this limit of acid concentration throughout distillation, falls within the scope of the present invention.

According to the preferred method of operation according to the present invention, the mixture of esters formed by absorption of olefines, if containing a benzine-like hydrocarbon, is referably first settled to cause this hydrocar n to separate as a top layer which is drawn off. The mixture is then dilutedfi and the dilute mixture is then hydrolyze'd under conditions preventing conversion of alk 1 radicals to polymers prior to distill- .ing the alcohols from the dilute mixture of alcohols and acid resulting fromthe hydrolyzation. The step of settling as just described may be omitted if desired.

Preferably the hydrolyzation of the ester mixture is carried out by heating the mixture with water under a reflux condenser until hydrolysis has been completed. The heating for hydrolysis is conducted so that substantially no alcohols or polymers are driven off during the hydrolysis. When the ester mixture has been diluted with 2 preferably four volumes of water and no alcohol is driven off thru the condenser during hydrolysis, conditions are automatically maintained such that no alkyl radicals are broken down to form polymers or like bodies. The

temperature of the mixture during hydrolysis is preferably not permitted to exceed 90 C. According to the present invention it is found desirable to dilute the ester mixture with at least four volumes of water before-hydrolyzing it. By hydrolizing in the presence of four volumes of water, the maximum yields of alcohol are obtained in the subsequent distillation, and although the yield ofalcohol when using four volumes of water-for hydrolysis is not a great deal lar er than when using 2 volumes of water, t ere is nevertheless a sufficient difference to change the operation from an unprofitable to a commercially profitable operation.

It has developed in practising the present invention that the ma 0r portion of the socalled polymers obtained when proceeding accordin to theprior common practice were forme during the distillation of the mixture of alkyl esters, the polymers so formed coming from the alkyl radicals in the esters having more than four carbon atoms in the molecules. According to the present invention, substantially no polymers are formed subsequent to the absorption step, and the yield of alcohols, more particularly of the more valuableheavy alcohols, is correspondingly considerably increased. As just stated, a maximum yield of alcohols is obtained when the mixture of alkyl esters is diluted with four volumes of water prior to hydrolysis, but the alcohol yield increases more slowly between dilutions of 2 volumes of water and 4 volumes of water, than for diluting up to 2% volumes. The higher dilution is decidedly advantageous in that it facilitates the separation of polymers contained in the mixture of alkyl esters from the alcohols formed during hydrolysis of the esters.

The hi her dilu tion also avoids formation of polymers or other bad smelling compounds, some of which are formed by deh dration of alcohols when less than four vo umes of water are used. The diluted mixture of esters may be allowed to stand for about two hours in which time most of the polymers rise to the surface and can be decanted prior to hydrolyzing the esters. If the polymers are not separated from the mixture by standing as just mentioned, they are dissolved to a considerable extent in the alcohols formed by hydrolysis. Some of the polymers are, however, held in the dilute ester mixture and these are removed as described below.

As above stated, according to the present invention the hydrolysis of the dilute mixture of esters is carried out preferably by heatin under areflux condenser, and preferably with a minimum quantity of reflux until hydrolysis is complete. During the hydrolysis just mentioned some light hydrocarbons, ethers and gas are driven off from the acid-alcohol mixture throughthe breather pipe of the reflux condenser. Completion of the hydrolysis is indicated, when a surface layer is present, by the fact that the color of this layer turns from brown to green. No advantage is obtained in continuing the heating .for hydrolysis after hydrolysis is complete, or usually for a greater period than four hours. While the operation of the condenser with a large 11: reflux during the hydrolysis is permissible and reduces the time for completion of hydrolysis it uses so much more fuel that no commercial advantage is apparent in sodoing.

As previously indicated, considerable dif- 1a ficulty has been encountered in removing the polymers, so-called, from the alcohols obtained from petroleum, and especially in removing the last traces of the polymers from these alcohols so as to roduce' alcohols hav- 121 ing a desirable odor. t will be understood that the sale price of the alcohols lighter than amyl depends at present in large measure on their odor. According to the present invention, the difficulties just mentioned are re- W duced ab initio in that the quantity of polymers formed is largely reduced. However, at the present time'no method has been found for preventing the formation of some polymers during the adsorption step when using an acid absorbing medium and such polymers necessarily appear in' the ester mixture before hydrolyzation thereof. According to the present invention the polymers are substantially removed from all but a small percentage of the alcohols formed during the process by absorption in alcohols heavier than amyl alcohol, or in other words, those having more than five carbon atoms in their molecules. Preferably hexyl -or heavier alcohol or a mixture of hexyl and heavier alcohols is used for absorbingthe polymers from the mixture of crude alcohols formed as described. In case the mixture of acid esters to be hydrolyzed does not contain suflicient alkyl radicals having more than five carbon atoms'to absorb .the esters.

the polymers from alcohols containing three or four carbon atoms, such heavy alcohols for absorbing the polymers may be added to the mixture of alkyl esters prior to drolyzation or to the mixture of alco ols and acid subsequent to hydrolyzation, but preferably the heavier alcohol is added to the ester mixture prior to hydrolyzation of If more convenient, however, the acid alcohol mixture formed by hydrolyzation may be distilled to produce propyl and butyl alcohols, or a mixture of these alcohols. This product so obtained is then diluted to such a gravity that the higher alcohols when added thereto will not dissolve in the propyl and butyl alcohols. The diluted alcohol or alcohols when treated with the heavier alcohol or alcohols to absorb the polymers from the lighter product will cause the hexyl or heavy alcohol containing the polymers to rise to the surface upon being allowed to stand quietly and the layer formed by the heavy alcohol and polymers is then decanted.

When, as is ordinarily the case, the mixture of'alkyl esters contains a moderate percentage of hexyl and heavier radicals, the hexyl alcohol and the alcohols heavier than hexyl formed during the hydroylsis absorb the polymers in the alcohol-acid mixture. These higher alcohols being to some extent insoluble in the diluted mixture, some of them rise to the surface carrying polymers with them and forming a surface layer. A considerable portion of the heavy alcohols, such as hexyl or heayier, do not separate, however, from the remainder of the alcohol-acid mixture during the hydrolyzation step owing to the agitation which accompanies the heating under the reflux condenser. When the hydrolysis is completed' and the heating stopped, the hydrolyzed solution is allowed to cool and an additional amount of the higher alcohols remaining in the body of the mixture thereupon comes to the surface carrying with it substantially all the remaining polymers and at the same time making the lower layers of dilute alcohols clear. .A material amount of hexyl and heavier alcohols, however, will ordinarily remain in the. clear body ofalcohols.

After the surface layer above mentioned containing the hexyl and heavier alcohols and the polymers has been decanted from the mixture of acid and alcohols, the acid-alcohol mixture is distilled. Preferably this dis- In the accompanying drawing, the figure illustrates in diagrammatic manner an apparatus adapted to carry out the process disclosed herein.

In the drawing, 2 indicates a chamber into i which gaseous material is introduced through an inlet at the point 4, said gaseous material containing olefines to be absorbed by acid within the chamber 2. Acid is introduced into the upper part of the chamber 2 through an inlet at the point 6 and flows downwardl through chamber 2 countercurrent to olefi econtaining material which rises up thro gh chamber 2 and passes out through anoutlet at the point 8. The olefine-containing material is scrubbed by the acid as the acid passes down through chamber 2 and chemical reactions-occur between the olefines and the acid whereby alkyl esters are formed. Any mineral acidmay be used for this purpose, but

sulfuric acid and phosphoric acid are the only ones which have been applied commercially. Alkyl esters and uncombined acid or acid alkyl esters pass out ofthe chamber 2 at the bottom throu h an outlet 10 which connects the bottom 0 chamber 2 with the top of a second absorption or reaction chamber 12. Liquid ol'efine-containing material is introduced into the chamber 12 thru the inlet at the point 14 and rises through chamber 12 countercurrent to the acid and alkyl esters which pass down through the chamber 12 from chamber 2. Additional chemical reactions occur within chamber 12 between the acid material and olefine material. It is desirable. to so regulate the flow of acid and olefine-containing material through the chambers 2 and 12 that practically all the acid is converted into esters, although it is seldom possible in practice to obtain 100% conversion of the acid into dialkyl esters. The ester material, or acid ester material, passes out 7 through chamber 2 and out at the point 8 4 ester and acid from warming while standing aving along with unabsorbed gaseous material. Preferably the material introduced into the chambers 2 and 12 is cooled before being brought into contact with the acid absorbing menstruum and cooling means. may be provided in the chambers 2 and 12 to absorb the heat of reaction and to maintain a fairly low temperature therein. Temperatures below 20 F. have the favorable effect of reducing the amount of olefine material polymerized in chambers 2 and 12. If the temperature is maintained so low as to substantially prevent polymerization, the speed of reaction is reduced below commercial requirements. Temperatures between 0 C. and 5 C. are suitable for absorption, however. Ester material passes from chamber 12 through connection 18 into a settling tank 20. Tank 20 is insulated to prevent the cool therein and the ester material is held in tank 20 long enough to permit light benzine-like hydrocarbons to rise to the surface and to be thrown off from the ester material thru an outlet at point 21. The ester material passes out from tank 20 through an outlet at the point 22 and is conducted through a connection 24 to a drowning tank 26. Tank 26 has an inlet for water at the point 28. In the tank 26 ester material is diluted with water, preferably to the extent of four volumes of water to one of ester material. Cooling means 30 are provided within tank 26 to prevent the rise of temperature therein. After dilution in the tank 26 a considerable percentage of.

the polymers in the ester material separates from and is decanted off through a connection 32 to storage. After the dilution and separation of some of the polymer material, the ester material is taken out of tank 26 through an outlet at the point 34 and conducted throu h a connection 36 to a hydrolyzer tank 38. ank 38 is preferably lead-lined so that acid formed therein by hydrolysis of the esters will not attack the tank. Tank 38 also contains heating means 40 and connected with the upper part of the tank 38 through a connection 42 is a reflux condenser 44. This h drolyzer tank 38 is preferably provided a so with cooling means (not shown) whereby the tank may be quickl cooled after a given batch of esters has en hydrolyzed therein. Reflux condenser 44 has a breather ipe 46 an out at pipe 50. After the ester materlal has been introduced into the tank 38 the heating means40 is operated to raise the leadin to a lead-tube condenser. 48

I temperature of the diluted ester mixture to the point where hydrolysis occurs between the water and the esters with formation of acid and alcohols. -While some of the esters would hydrolyze at normal atmospheric temperatures, some of them require higher temperatures in order to form the corresponding alcohols. On the other hand, if the heating is pushed beyond a certain point a useless expenditure of fuel is incurred and possibly some alkyl radicals would be polymerized. It has been found that a suitable rate of heating the ester material in the tank 38 to produce hydrolysis is that which produces only such an amount of reflux flowing back into the tank 38 from the reflux condenser 34 as to keep the liquid in tank 38 well mixed. During the heating and hydrolysis of the esters in tank 38 no alcohol vapors are permitted to escape from the reflux condenser through the pipe 46 and substantially no polymers escape in this way. However, certain light polymer-like material and condensable gases pass over through the pipe '46 and are condensed in the condenser 48 as Well assome gaseous uncondensable material. Such liquid as is condensed in the condenser 48 may be stored or run to waste as desired. When the dilute ester mixture is hydrolyzed as just described, there'is no breaking down of the esters or alcohols or formation of polymers.

The heating for hydrolysis is continued until all the esters have been converted into alcohols and acid. During the heating for tank 26 forms a solution with some of the heavy alcohols of more than five carbon atoms and rises to the surface in the tank 38 forming a surface layer. Completion of hydrolysis is indicated when the surface layer in tank 38 turns temporarily from brown to green. Upon cooling the brown color is regained. This 'chan e of color indicating the completion of hy rolysis in tank 38 occurs usually in about four hours after the heating is begun, but may occur sooner if the heating has een pushed. It is desirable not to continue heating the hydrolyzed mixture after hydrolysis has been completed not only because of the unnecessary use of fuel in so-doing but because of danger of breaking down of some of the alcohols previously formed. When hydrolysis has been completed therefore, the heating is immediately interrupted andthe resulting mixture of alcohols, acid and water is uickl cooled by means of the cooling means znot s own) previously mentioned. As the mixture becomes calm after the refluxing has ceased, an additional amount of heavy alcohol-polymer solution rises to the surface.

lyzed in tank 38 the resulting mixture of acids outlet at the point 52 and conducted through a connection 54 to a lead-lined still 56. Still 56 has a dephle mator 58 connected thereto,

the upper end dephlegmator 58 being connected in turn through pipe 60 with areflux condenser 62. Reflux condenser 62 is connected in turn by pipe 64 with a condenser 66 designed to condense vapors passing into it through pipe64. The material in still 56 is heated and distillation is carried on at atmospheric pressure. At this pressure, a mixture ydrolyzed as above described" previous to distillation does not form decomposition products during distillation.

As the temperature in still 56 rises various products are driven ofi' in succession. The first material coming from the condenser 66 is chiefly a mixture of ketones. As the temperature approaches 80 C. some isopropyl alcohol begins to come over through the condenser 66 and a cut is made at this point, material condensed below 80 C. being conducted through a'line 68 to storage.- Such isopropyl alcohol as is contained in this first out can be separated from the ketones and recovered by subsequent distillation. After.

the temperature in the still 56 reaches 80 C. a substantially constant boiling point is reached at which an isopropyl alcohol water mixture is driven off from the still 56 and condensed in condenser 66. The cut for crude isopropyl alcohol is made when the temperature in still 56 has reaches 82 C. The isopropyl alcohol cut is conducted from the condenser 66 through a connection 7 0' to crude isopropyl storage 72. The constant boiling mixture of isopropyl alcohol and water boils at aproxjmately 805 C. and the crude isopropyl out just mentioned includes approxiconducted from condenser 66 by a connection 7 4 to storage tank 76. -When the tem erature has risen to point 86 C. substantia ly butyl alcohol and water begins to come over and the out for the isopropylbutyl mixture is therefore made as-soon as the temperature reaches 86 C. When the temperature in still 56 is 86 C. or above, but below 88 C'., a butyl alcohol water mixture .is driven off from still-56 and condensed in condenser 66. It is conducted from the condenser 66 through the connection 7 8 to the stora'ge80.

en the temperature in still 56 reaches 88 G. a cut is made and beginning at 88 C.

material from still 56 condensed in condenser 66 is thrown into a cut for higher alcohols.

' The higher alcohol is conducted from con- 100 C. Of course many of the higher alcohols in the mixture to be distilled in still 56' have boiling points considerably above 100 C. Nevertheless if the distillation is-pushed somewhat they are carried over within the temperature range indicated owin to the water vapor being driven olf from t e still and so are protected from decomposition. i In tank 84 the material separates into two layers. The surface layer contains the amyl alcohol together with a good deal of water, a little butyl alcohol and a little of thealcohols higher than am 1. vThis water layer is drawn off from tan 84 through an outlet at the point 86 and conducted to storage. It is-afterward given special treatment to recover the commercial grade of amyl alcohol.

The lower layer forming in tank 84 is composed of hexyl and'heavier alcohols and is taken out of tank 84 through an outlet at the point 88 and conductedthrough a connection 90 to a storage tank 92. This heavy alcohol layer is composed of a mixture of higher alcohols, allsubstantially insoluble in water, and most if not all of them incapable of withstanding their boiling temperatures without more or less decomposition. Special treatment is therefore re uired to separate the individual alcohols from this fluid mixture.

While it .has been found possible to separate the"amyl alcohol from the heavy alcohols in the water layer by distillation, no commercial way was known until recently to separate the hexyl and heavier alcoholsto obtain good smelling roducts. A special method of treating the eavy alcohols has been discovered by me which overcomes the difficulties in this connection. Said special method comprises. distilling a mixture of heavy alcohols in vacuo to maintain temperatures below those at which the heavy alcohols decompose.

Said special method, however, forms no part of the present invention and is not claimed herein.

The solution of heavy alcohols and polymers mentioned above as decanted from the acid-alcohol mixture after hydrolysis also requires special treatment if the heavy alcohols are to be recovered therefrom. Such special treatment, however, forms no. part of the present invention and is not claimed herein.

For instance, commercial amyl alcohol is required to be substantially anhydrous. A. convenient method of dehydrating the amyl alcohol cut to meet the commercial requirements is to distil it with the still butts remaining from the rectification of the butyl alcohol cut, or to distil it with butyl or other lighter alcohol. This process of dehydration, however, forms no part of the present invention and is not claimed herein.

While one specific process embodying the novel steps of the present invention, as well as one specific apparatus for carrying out the same, has been described in considerable detail, it is to' be understood that this description is illustrative only, and for the purpose of making the invention more clear, and it is not intended that the invention shall be construed as limited to details of the description except in so far as such limitations have been included in the terms of the following claims in which it is the intention to claim all novelty inherent in the process according to the present invention as broadly as permissible in view of the prior art.

It will be understood also that wherever the phrase alkyl esters appears either in the description or claims, it is used, except where otherwise indicated, to include either acid or normal esters or mixtures of such esters. In particular it will be understood that the acid used in absorbing the olefinesis not a feature of the present invention which is in nowise limited to treatment of olefines by sulphuric acid or to treatment of esters of sul huric acid. claim:

1. In the process of making alcohols from petroleum products containing olefines, the steps comprising absorbing olefines from petro eum products by a mineral acid with the formation of alkyl esters and polymers, and afterwards separating and removing polymers formed in the process by absorption in an alcohol having more than five carbon atoms in its molecule.

2. In a process of producing alcohols from petroleum. products containing olefines, the ste s comprising absorbing olefines from petro eum products by a mineral acid with production of alkyl esters and polymers, and

thereafter removing the polymers from theprocess by absorption in a secondary alcohol having more than five carbon atoms in its molecule.

3. In the process of producing alcohols from petroleum products containing olefines, absorbing olefines from petroleum products in a mineral acid to form a mixture of alkyl esters including alkyl radicles having more than five carbon atoms and also including polymers, hydrolizing1 said mixture to form alcohols, absorbing t e pol ers in an alcohol containing more than ve carbon atoms in its molecule, se arating the alcohol conta ning polymers om the remainder of the mlxture and distilling ofi the remaining alcothols from the acid formed during hydrolyza- 4. In the method of producing-alcohols from petroleum products containing olefines, ab-

sorbing olefines from petroleum products by a mineral acid to form a mixture of alkyl esters and polymers, absorbing said polymers in an alcohol having more than five carbon atomsin its molecule, removing said polymers and alcohol from the process, hydrolizimthe alkyl esters to produce alcohols and acid, distilling said alcohols from said acid, and rectifying and dehydrating said alcohols.

5. In the process of forming alcohols from olefines, the steps comprising absorbing a mixture of olefines in a mineral acid to form a mixture of esters, diluting the mixture with water to maintain the acid concentration in said mixture at substantially 15%, and bydrolyzing the resulting mixture under reflux condensing conditions at temperatures not exceeding about 90 C. for a period of approximately four hours.

6. In the art of producing secondary alcohols from petroleum products, the improvement comprising absorbing olefines some of which contain at least five carbon atoms from petroleum products by mineral acid to form a mixture of alkyl esters, hydrolyzing said mixed esters to form a mixture of alcohols and acid, absorbing substantially all the polymers in said mixture by alcohols formed during "said hydrolization and having at least carbon atoms from the acid an depolymerized alcohols. 1

7. The method of treating a l sulphates, the alkyl group or groups of w ich contain more than four carbon atoms, which comprises diluting and hydrolyzing said sulphates with water to form sulphuric acid and an alcohol or alcohols corresponding to said alkyl group or groups, removing the alcohol from the hydrolyzed acid mixture by distillation, and maintaining the acid concentration during distillation at a value not substantially exceeding 15% sulphuric acid, by adding water to the said mixturebeing distilled. 8. The process of removing polymers from a mixture of polymers and hydrolyzed alkyl esters, which com rises extracting the mixture with an alco 01 having more than five carbon atoms in its molecule whereby the said polymers are dissolved in said alcohol and removed therewith from said mixture.

9. In the process for manufacturing alcohols' from alkyl esters in which the alkyl esters are hydrolyzed under controlled temperature conditions to alcohols and acid and the alcohols distilled from the resulting mixture, the improvement which comprises exthat equivalent to 15% sulphuric acid.

10. In the process for manufacturing alcohols from alkyl esters of an inorganic acid in which the esters are mixed with water and hydrolyzed to produce alcohols and acid, the improvement which comprises mixing a quantity of the esters to be treated with sufiicient water to adjust the concentration of the acid in the ester mixture to the extent that it does no exceed the equivalent of about 15%, allowing the resulting mixture to stand for approximately two hours, thereafter heating and refluxing the mixture for a substantial period of time to completely hydrolyze the esters in said mixture to alcohols and acid, allowing the hydrolyzed mixture to stand and. stratify to thereby form a layer of higher boiling point alcohols and polymers and an acid solution layer containing alcohols, and separating said layers by decantation.

In testimony whereof I a-fiix m signature.

SYLVAN R. ERLEY. 

